Ii lost that thing on one of my previous gassers. I rode without it for a long time not even knowing. My kickstand felt funny and I kept tightening it. I finally noticed that it was the bottom bolt and subsequent missing roller. I think you need the roller to keep your chain from slapping around so much, and to keep your kickstand mount in tact.
I only just replaced mine. I only found out there was one there when I ordered a whole set from scotties. he asked about the kickstand one and I said are you sure?
Anyway after a few pretty hectic rides it is still there.... so far.
Cheers Mark
DRC makes a good ones, with good bearings, you need tonloctite the srew.
Runing w/o is not a big problem until you break a chain, w/o the rollers the chain slaps e erywere and may damage engine cases and/or block the rear wheel.
Thanks for the tip HuskyDude! Too easy! I've been changing tires for folks, and some of them have colored rims. I hate the really nice ones! I just slam my own rims, I don't have any regard for scratching them, long live silver rims.